Process and apparatus for refining oils



June 30, 1931. c. w. S'ILRATFORD 1,812,612

PROCESS AND APPARATUS FOR REFINING OILS Filed Nov. 24, 1926 2 Sheets-Sheet 1 .2- m all? 1|.l." 9}

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PROCESS AND APPARATUS FOR REFINING OILS Filed Nov. 24, 1926 2 Sheets-Sheet 2 N 3\ A w :\\\\\\\\\\E Q 5411 lfiy z F \\\\\\\\\\s" AA" Kalli/111 1/11 1111/ 1/ I N V EN TOR Patented June 30, 1931 i I i UNITEDSTATES PATENT orrlcs CHARLES WALGOTT STRATFORD, OF SAN FRANCISCO, CALIFORNIA.

PROCESS AND APPARATUS FOR REFINING OILS Application filed November 24, 1926." Serial No. 150,488.

This application is a continuation in part, still surface Without the aid of mechanical of a prior application Serial No. 1,947 filed mixing devices, the primary current spread- September 8th, 1925. ing the oil into a rapidly moving liquid sheet There hereinafter described invention rein contact with the inner still surface and the 5 lates to the refining of liquid hydrocarbons, secondary current mixing it in the mass. The 7 although its principles and benefits may be oil may also be said to travel in a thin layer very advantageously applied in handling in pressure contact with the inner heated other liquid substances in efiecting their heat surface of the still while circulating thereing and vaporization. Insomuch asmy invenover.

10 tion has particularly amongst itspurposes the The applications of my novel processand or; handling of liquid hydrocarbons, I will ilapparatus for circulating liquid hydrocarbon lustrate and describe its embodiment in the in mass within an enclosed heated container, well known type of cylindrical oil still now while spreading it in a rapidly moving sheet generally in use in oil refineries. over the inner heated surface thereof to ef- Among the objects of my invention are, fect an increased efliciency in its heating and as keeping the inner cylindrical surface of the vaporization, will be obvious to those skilled still free from the deposition of solids by in the art. v V causing the liquid hydrocarbon to move up The present application has incorporated idly and continuously over the heated surtherein features additional'to those shown in 1' face of the still, increasing the rate of firing the prior application of which this is a conis of the still by protecting its bottom as ext1nuation in part. The principal object of posed to hot furnace gases with a constantpassing the charged oil over pans prior to its 'ly moving liquid mass, increasing the rate introduction to the oil body in the still, is to of evaporation of theliquid hydrocarbon per cause vaporization of a portion of this oil unit of heating surface exposed. The accom-- at a lower meanboiling temperature than plishment of these objects enables me to would otherwise be the case were the oil materially increase the capacity or output of nnmediately mixed with the oil body in the the still while protecting its metallic surstill. The oil body has a materially higher faces againstoverheating, effecting economies mean boiling temperature than the oil I t not now obtainable in refining oil as charged charged. Therefore, if the charging oil is in volume in a still of this type. immediately mixed with the oil body in the My process is distinguished by the fact st1ll,the resulting composite will have a highthat 1 cause a continuous circulation 0r er mean boiling temperature than with the stirring of the mass or total volume of oil use of pans, as described. f

: .1 in thestill while simultaneously forcing it to A further advantage i travel at high" velocity over the inner-heated tributing the charging stock, on its introducsurface of the still in a rapidlymoving'sheet tion to the still, by passing it over pans havwhile stilling. ing in the bottom thereof a roughened sur- This I do by discharging the oil within face which maintains the oil in a constant 0 the still under pressure and with velocity state of agitation until its discharge into the so through nozzles against itsinner cylindrical oil body, thus affording an opportunity for surface, a dual movementof the oil in well the lighter fractions thereof to be distilled. defined circuits taking place. These two before the liquid oil is combined with the oil movements of the oil I will term anddescribe body in the still. Furthermore, the present as primary and secondary currents or moveapplication discloses ameans for withdrawments, and I desire it to be understood that ing the oil from the system after treatment, the stirring or circulation of the oil in mass which is positive in operation and easily conand its rapid travel in contact with the inner trolled as the draw offline is connected diheated surface of the still is entirely the rerectly into the discharge from the pump sult of the force of its discharge against the which is circulating the-oil in the still. i 1

11 the method of dise5 Fig. 1.,

now takes place in the stills 7 of these troughs or In order that a comprehensive understanding may be had through the illustrative embodiment of my invention herein set out, reference should be made to the accompanying drawings, in which Fig. 1 is a longitudinal section of a cylindrical oil still with heating furnace of the type now generally employed in refining oil. The still is shown fitted with the apparatus of my invention, which involves in the present setting a centrifugal pump mounted within the still with suction and discharge pipes. The suction of the pump is set to draw the oil from near its bottom and to create a; partial vacuum below the surface of the oil level while the discharge of the pump is connected to a pipe manifold with jets or nozzle outlets directed to discharge the oil over and against the bottom of the still.

Fig. 2 is a section taken on line 2-2 in to show the oil discharge manifold and its nozzles and the relation of the nozzl'es to the inner cylindrical surface of the still.

Fig. 3 is an enlarged sectional view of one of the nozzles in the manifold showing its discharge opening adjacent the inner surface of the still bottom.

Fig. 4 is adiagrammatic view showing generally how the dual movement of the oil is effected" within the still by my process. The primary movement of the oil along the inner surface of the cylindrical still at high velocity is denoted by the full line arrows A, while the secondary movement of the oil within the mass is denoted by the dotted line arrows B. The oil level in the still is denoted by the line XY.

The result of this twofold movement is a rapid heat exchange through the" still bottom and high rate of vaporization of the oil while stilling.

In this manner I also overcome all unde sirable localized overheating of theoil which which are charged with oil in volume and which is the cause of deposition of solids therein.

In the drawings. the numeral 1 designates a standard type of enclosed cylindrical container providing an oil still. T he still 1 is set over a refractory lined furnace and receives heat against its bottom in the present instance from the hot products of combustion of an oil lire, although heat from any source may be employed so long as the temperature is sullicient to effect the aporization of the liquid hydrocarbon in the still.

The still 1 is provided with an oil filling inlet 2, controlled by a valve 3. The oil inlet terminates in the still in separate discharges? and 2 flowing the oil asit enters the stillon to inclined pans or troughs 3 which are supported in the upper part of the still by brackets 4. In the bottom pans placed a coarse a Y connection ,-the

Wire mesh 5 which serves to keep the oil, during its passage over the pans, in constant motion or in an agitated or rippling condition so that a greater surface of the oil is exposed to the heat of the surrounding vapors in the still. In the bottom of the lower ends of the upper troughs 3 are apertures which permit the oil to pour down onto the lower inclined troughs 6 where its direction of flow is reversed as shown by the arrows in Fig. 1. TlIGSu troughs are positioned above the liquid level of the oil contained in the still. After passage over the lower troughs, the films of oil are discharged into the oil body where it receives its ultimate heating. Near the bottom of the still is provided aclean-out line 7 controlled by a valve 8.

The still, as previously suggested", is supported above a furnace 9 preferaliily heated by means ofgas or oil burners diagranimatica'lly shown at 10. The top of the still 1' may be provided with a dome 1'1 to'which the outlet for withdrawing the vapors liberated during the stilling operation is connected. Alsothe vapor line 11 ma he connected directly to the still. Mounted within the still 1 is a pump 12 and mounted on the exterior of the'still is an electric motor 13. Suitable shaft transmission means lconnectsthe pump 12 and the motor 13 through the glandand stufling box 15. The pump 12 is fitted with a suctionpipe 16 and the discharge pipe 17. The distributing manifold 17 comprises an assembly-0f pipes connected to the pump discharge 17. Headers 18 running laterally of the still l and connecting pipes 19' running longitudinally thereof; 'i'lie headers 18 are so set with reference to the inner surface of the still. bottom as to bring the longitudinal pipes 19 intoclose proximity theretoj Inserted or fitted into the pipes 19, at suitably spaced intervals, are nozzles 20. The nozzles 20 provide a means so that oil pumped through the manifold 17 will be discharged against the inner surface of the still 1' at a high velocity. The number of nozzles employed is governed by the area oftlie heated surface over which the oil is discharged, and the intensity desired of the liquid movement desired to be effected.

Again, the rapidly moving liquid over the heated surface being the result of the partia vacuum created by the pump (spread of the oil around the outlets of the jets), itis obviousthat with a given oil discharge pressure the spacing of the nozzles over the surface will govern the continuity of t rapidly-moving liquid sheet covering formed over the surface. Connected into one on d of the manifold 17 is the discharge line 21,-the discharge flow of oil through by a valveshell of the still or in any convenient operator. By means of this valve 22'. a conthis line being controlled 22 positioned just outside of the position. outside of-the still for manipi'llationby the stant level may be maintained in the still. A positive discharge flow is assured by the fact that the residual oil is taken directly from the circulating pump discharge. It will be noted that any equivalent form of oil discharge manifold located with nozzles adj acent to the inner without departing vention. A

When it is desired to operate the still, oil is run in through valve 3 and inlet 2 until a quantity suitable for stilling is present. The dotted line XY represents generally the surface of such a body of oil. This body of oil is maintained substantially constant in volume by the addition of raw stock through the charging inlet 2 when necessary. When the still is charged it is brought up to any desired temperature. At a predetermined temperature the circulating pump is started and the oil circulated within the still. The pump, creates a vacuum below the level of the oil, and the oil is forced through the discharge manifold 17 and the jets 20 against the inner heated surface of the still bottom 1, thereby effecting the continuous liquid movement of the process. hen the oil has been brought to the desired temperature at which the stilling operation is carried on under the most eflicient operating conditions, the still may be operated continuously by the introduction of charging stock through the inlet pipe 2 and the oil level kept constant in the still by a continuous discharge of the residual oil material through the pipe 21 controlled by the valve 22.

The embodiment of my invention herein illustrated and described is for the purposes of setting forth its principles and advantages, and it is understood that the operation is particularly suitable for distillation of oil under so called atmospheric pressure or under reduced pressure conditions, the circulation within the still affording considerably more efficient conditions of operation as to heat transfer than the normal type of shell still operation where the circulation within the oil body is dependent upon convection currents set up by the oil in contact with the heated surface. 7

It is understood that the apparatus and pipes exposed are heavily insulated to prevent loss of heat'by radiation. As mentioned, vapors discharged are taken off from the top of the dome 11 through a vapor ipe 11 While the control of the draw off is shown as a valve 22 in actual commercial practice, this hot residual oil is passed directly from the still through heat exchangers, not shown in the drawings, and the control valve or valves situated on lines through which the cooled oil passes;

Furthermore a liquid level control, not shown, may be employed to automatically still surface may be used from the spirit of the in regulate the discharge flow, and thereby control the liquid level in the still.

While the operation is disclosed and described as continuous single still operation, the oil circulation may as well be applied to a battery of stills connected in series so that instead of passing. the discharge from the initial still to heat exchangers the oil is introduced into the pans of the next succeeding still. The discharge from the final still of the battery is passed to heat exchange and to storage. 7

I claim as my invention:

1. An apparatus for refining oil, comprising, in combination, a still adapted to contain a maintained quantity of oil during stilling, circulating means within the still adapted to draw oil from the oil body and means to dis charge it under pressure in a plurality of separate streams against the inner heated surface of the still increasing heat exchangeand to produce rapid circulation in the oil body, and withdrawal means connected to the circulation means for drawing off treated oil from the body of the still. I

2. The process of refining oil in a still containing a maintained quantity of oil during the stilling operation, which comprises continuously drawing the oil from adjacent the heating surface of the still and thereby creata;

ing a partial vacuum below the oil level, in discharging the drawn oil in a plurality of separated streams aidedby. the partial vacuum against the surface under such pressure and in such predetermined relation to each other as to cause each of said streams to form a thin, laterally extending, rapidly moving film of oil against the heated still surface and the several films so formed to mutually coact V to induce a rapid circulation of oil upwardly from said heated surface toward the top of the oil body and downwardly to points adjacent the heated still surface, whereby to induce a rapid circulation of the entire body of oil within the still and to cause its repeated contact with the more highly heated portions thereof, and in continuously bleeding a portion of the oil from the system from/the di charge of the circulating means.

3. An apparatus for refining oil, comprising in combination, a still, induction and eduction means associated with the still, circulating means within the still, a plurality of connected tubes having jets adjacent the heated surface of the still, said tube system connected with the discharge of the circulating means, a secondary line connected to the discharge line of the circulating means for withdrawing oil from the still and maintaining a constant level therein.

4. A process for refining 011 in a still comprising the steps of distilling a maintained quantity therein, continuously drawing oil from the body and discharging the drawn oil in a plurality of separate jets against thelfi I heated still surface,:saidjets adapted to move the oil, overthe heated surface in rapidly niovin-gfilnis, and inducing a circulation in the oil body, continuously removing a portion of the oil from the still by bleeding a stream of oil from the tube circulatingsysteni, and supplying oil to the body.

5. An oil still comprising a circulating system entirely contained therein operating .at relatively higher-pressure than the still an inlet oil supply line and a discharge pipe connected with the pressure circulating systern.

CHARLES WVALCOTT *STR'ATFORD. 

